Ribbon feeding mechanism



FIP8212 XR 291079039 Feb- 1, 1933 J. F. LVENTHAL Er A1. 2,107,039

RIBBON FEEDING HECHANISM Filed Sept. 27, 1954 2 Sheets-Sheel 1 1'" Uf ENR ATTORN EYS v A .-..vv n... I nknxn. QAM

Feb. 1, 1938. J. F. LEVENTHAL ET Al. 2,107,039

I RIBBON FEEDING MECHANISM Filed Sept. 27, 1934 2 Sheets-Sheet` 2 (Mwumdgl/S @i A ORNEY Patented Feb. 1, 1938 UNITED STATES PATENT OFFICE2,107,039 RIBBON FEEDING BIECHANISM Jacob F. Leventhal and N. Y.,assignors to Le Samuel Bagno, New York,

venthal Patents, Inc., New

1 0 Claims.

This invention relates to motion picture apparatus and more especiallyto lm feeding devices therefor.

At present, motion picture film is customarily provided withperforations which cooperate with sprocket teeth of feeding mechanismoperated to feed the flim at a constant picture rate. In some types ofnlm feeding mechanism, the perforations are engaged by the teeth of anintermittent l0 pull-down sprocket or claw mechanism as well as by theteeth of a regulating sprocket, while in other types of feedingmechanism perforations are engaged only by the teeth of the regulatingsprocket. Sprocket feeding has the undesirable feature for continuousillm feed apparatus and sound-on-film apparatus that there is always alack of perfect correspondence between the pitch of the sprocket teethand the pitch of the lm perforations. The film, therefore, is not fed atuniform velocity, but rather at slightly irregular velocity. This lackof correspondence is due to lm shrinkage and increases with the extentof film shrinkage with consequent increase in the irregular velocity ofthe lm. 'I'he ideal condi? tion of uniform velocity of film feed cannotbe realized by sprocket feeding.

An object of this invention is a film feeding mechanism which insuressubstantially constant film velocity at a definite picture rate.

According to the present invention, the film is provided along one edgewith alternate light transmitting and light obstructing areas. Such filmis fed between a light sensitive element and a light source and movablemeans are provided to cooperate with the light transmitting and lightobstructing areas to control the amount of light transmitted from thelight source to the light sensitive element. The movable means isoperated at a predetermined speed governed by the picture rate of theapparatus and the nlm is fed by means controlled as to speed by thelight sensitive element. By this mechanism, the velocity of the filmfeed is maintained substantially constant and the film is fed at adenite predetermined picture rate. Such lm feeding mechanism isparticularly adapted for continuous-type projectors and for intermittentprojectors of the beater or similar type feed.

Other objects, novel features and advantages of this invention willbecome apparent from the following specification and accompanyingdrawings, wherein: A Fig. 1 is a diagrammatic illustration ofacontinuous type projector equipped-with iilm feed- 5&5I ing meansembodying the invention;

Fig. 2 is a similar view of a continuous type projector equipped with amodified form of lm feeding means embodying the invention;

Fig. 3 is a vertical section through lm feeding mechanism of the typediagrammatically illustrated in Fig. 2;

Fig. 4 is a section on the line 4-4 of Fig. 3;

Fig. 5 is a section on the line 5--5 of Fig. 3;

Fig. 6 is a diagrammatic illustration of a modied embodiment of theinvention;

Fig. 'I is a diagrammatic view of a further modification of theinvention;

Fig. 8 is a fragmentary elevation of Fig. 7;

Fig. 9 is a fragmentary view similar to Fig. 'l of a modication thereof;

Fig. 10 is a diagrammatic further modification; and

Fig. 11 is a plan view of a section of lm for use with the hlm feedingmechanism.

Referring now more especially to Figs. 1 to 3 inclusive, i0 is a lightsource, ll the reector therefor, and ,I2 the condenser lens whichdirects a beam of light through the iilm gate i3 to a rotatable opticalcompensator I4. Both in this flgure and in the succeeding figures, the25 compensator M may be of any of the known devices operative, whenrotated in timed relation to a continuously moving film, to producestationary screen images of pictures on the lm. It is specifically shownas a refractor` having two pairs of plane parallel faces and operativeto compensate four pictures for each revolution thereof. Means later tobe described are provided for feeding the lm at the rate of fourpictures for each rotation of the compensator. Each compensation cyclecomprises rotation of the compensator through one quarter revolution.With a compensator having a different number of faces, the number ofiilm pictures compensated per revolution and the extent of rotation ofthe compensator for a compensating cycle would be correspondinglyvaried. The compensator Il is driven by a motor i6 andlens l1 serves inthe usual way to project the picture to the usual screen. The film Fpasses between a guide roller I9 and an obturator or control drum 20which is rotatable with a gear wheel 2l which meshes with a gear wheel22 rotatable with the compensator I4. From the drum 20, the film Fpasses through the lm gate I3 and between friction rollers or drums 23and 24, the drum 23 being driven by a motor 25.

The film F (see Fig. 11) may be unperforated, but is provided along oneedge with alternating light transmitting and light obstructing areas.

sectional view of a provided a light sensitive element or photoelectriccell 2l which receives light from the source 21 through an aperture 25.The photoelectric cell 2li is connected to a power ampliner A, theoutput of which is connected to the motor 25 and is enective to vary thespeed of the motor 25 in a manner later to be described.

In the apparatus disclosedin Figs. 2 to 4 inclusive, the drum 22 iscarried by bolts 2l threaded into a spider 22 rotatably mounted on ashaft 22 which extends through and is keyed to a gear wheel 24 having ahub 25 journaled in the frame 25 of the apparatus. On each bolt 2| isrotatably mounted a pinion 21, both of which mesh with a pinion 28 nxedto the shaft 22. A disk 22 is provided with a cylindrical flange havinginternal teeth l0 meshing with the pinions 21 and external teeth 4Imeshing with a worm 42 driven by the motor 25. The gear wheel 24 mesheswith the gear wheel 22 fixed to the shaft on which the compensator Il ismounted.

The relation between the gears 2| and 22 and the number and spacing ofthe apertures 25 is such that one aperture passes between the lightsource 21 and the photo-electric cell 25 for each compensation cycle ofthe compensator I4. The diameter of the drum is such that the surfacespeed thereof is slightly less than the linear speed of maximum shrunknlm fed at the rate of one picture per compensation cycle. 'I'he drum 22is operated at the proper speed under control of the photo-electric cellto feed the nlm at the rate of one picture per compensation cycle.

'I'he drum-22 draws the nlm through the nlmgateandaroundthedrum2lisothataseach aperture approaches the edge of theaperture 22a a transparency on the nlm registers to some extent with theaperture, thus regulating the amount of light transmitting to thephoto-electric cell. If the nlm speed is too slow the registration willbe small and the amount of light passing to the photo-electric cell willbe correspondingly small. 'I'he photo-electric cell thereupon decreasesthe speed of the motor 25 to decrease the speed of the drum 22 sunicientto correct the condition. If the nlm speed is too high, the registrationwill be great and the amount of light passing to the photo-electric cellwill be correspondingly great. The photo-electric cell thereuponincreases the speed of the motor 25 to increase the speed of the drum 22sunicient to correct the condition. The relationship between the drumapertures 25 and the nlm transparencies has the same eifect as sprocketteeth and perforations with respect to obtaining framing of the picture.The nlm will always be advanced exactly one picture frame for eachcompensation cycle and accurate framing will result. At starting, eventhough no registration exists, the desired condition will automaticallybe arrived at after a short running time.

In the arrangement disclosed in Figs. 2 to 4 inclusive, primary rotationof the drum 22 is effected by the motor l2 through the gear iraincomposed of gear 22, gear 2l, shaft 22, pinion 22, pinions 21 andinternal ring gear II and secondary rotation of either additive orsubtractive nature is enected by the motor 2l through the worm 42, wormgear 4i and internal ring gear 4l. Relationship of the gears in the geartrain above specined is such that with the disk 22 stationary the drum22 would be rotated more slowly than would be required lto feed the nlmat the desired rate of one picture per compensation cycle. The motor 25is. therefore, always driving the disk 22 and variation of its speedenects regulation of the speed of the drum 22.

In the arrangement shown in Fig. 1, the speed of the drum 22 iscompletely unrelated inherently to the compensator speed. Therefore, thecorrections enected by the governor drum pertain to the speed of thefeed drum 22 as a whole. Thus, if the correcting system has a plus orminus tolerance of say 2%, the nnal error will be a 2% error, whereas inthe arrangement shown in Figs. 2 to 4 inclusive, the nnal error would beonly a fraction of the tolerance error.

The modincation disclosed in Fig. 6 relies upon the use of anelectro-magnetic brake to regulate the nlm speed. In this modification,the motor i6 drives the compensator Il, which is in turn geared to thegear wheel 2i which carries the governor drum 2li. The feed drum 22 isdriven by a motor 25 which tends to drive the feed drum at too high aspeed. The photo-electric cell 2n is connected with the neld winding ofan electro-magnet 42, the poles of which receive between themselves theiron disk 44 mounted on the armature shaft of the motor 25.

'I'he nlm F passes around the guide roller il and over the governor drum20 as before and controls the passage of Alight to the photo-electriccell 2l as previously described. When the nlm F runs too fast; thephoto-electric cell is enective to increase the strength of theelectro-magnetic brake and thus slow down the motor 25 to the properspeed required to enect feeding of the nlm at the rate of one pictureper compensation cycle.

The arrangement disclosed in Figs. '7 and 8 is a modincation of thearrangement disclosed in Figs. 2 to 4 inclusive. in which the governingdrum 20 is replaced by a governing disk 45 having a spiral slot 46 whichis adapted to register with the transparencies in the nlm F. 'I'he slotIl is eqral in width to the height of the transparencies and the ends ofthe center line of the slot are offset from each other by a distanceslightly less than the space between the center lines of transparenciesof a mammum shrunk nlm. The disk 45 is arranged to rotate once for eachcompensation cycle and the amount of registration of the slot 46 with anlm transparency depends upon the relative speeds of the nlm and thedisk. If the nlm is traveling too fast, the passage of light to thephoto-electric cell is varied to cause the motor 25 to be slowed down toremedy the condition and if the nlm is traveling too slowly, the reverseaction is enected.

In the modincatlon disclosed in Fig. l0, the compensator I4 and the gear22 are mounted on a shaft 22a. driven by the motor I5 (not shown). Ihegear 22 meshes with the gear 2| and with the gear 24 on which is mountedthe motor 25. The armature shaft of the motor 25 is connected throughsuitable reduction gearing l1 with a shaft 48 coaxial with the gear 2l.The drum 22 is mounted on the shaft 42. Energizing LIWHIIILH current issupplied to the motor 2i by way of stationary brushes 25c and rings 25dcarried by the gear 24, the energizing current being controlled by thephoto-electric cell 2l (not shown). 5 ln this modification, the drum 23draws the film through the film gate I2 and over the drum which are notshown in this figure but which are the same as in Fig. 3. Primaryrotation of the drum 23 is effected by bodily rotation of the 1o motor25 about the axis of the shaft and secondary rotation is effected byrotation of the amature of the motor 25, thus causing differentialrotation of the shaft 48 with respect to the gear 3l. The relationshipof the gears 22 and 15 24 is such that with the armature shaftstationary, the drum 23 would be rotated more slowly Vthan would berequired to feed the film at the desired rate of one picture percompensation cycle. The motor is. therefore, always relied 2 upon torotate the shaft 48 with respect to the gear 24 and variation of itsgleffects regulation of the speeds f the drum 23. 'I'he rate of rotationof the armature shaft s controlled by the photo-electric cell and thefilm feed velocity 25 is thus regulated. It is evident that in themodication disclosed in Fig. 10, there will be less gear shake or gearvibration than in the modification disclosed in Figs, 1 to 4 inclusive.

The circuit for the exciter lamp 21 may be provided with a rheostat 21aas shown in Fig. 3 to permit variation in the current supplied to thelamp either to compensate for decrease in brightness of the lamp fromdeterioration or to compensate for anychange of electrical charac-.teristics of the control and/or operating circuits. Although theinvention has been disclosed as embodied in a projector, it is evidentthat it may equally well be embodied in any motion picture apparatus ofthe picture cycle type such for example as a camera and it is intendedthat the claims shall cover all apparatus of this type as well asprojectors. In the claims, the film feeding member is designated a drumto distinguish from a toothed member such as a sprocket and it isintended to cover both cylindrical and frusto-conical members by thislterm.

Fig. 9 illustrates a modification of Figs. l and 8 in which the disk 45is arranged in a plane removed from the lm plane and the requiredregistration of the slot 46 and light transmitting areas of the nim F isobtained by voptical imagery through the medium of a lens 46a.

We claim:

1. In a ribbon feeding apparatus comprising a radiation emittingelement, a radiation sensitive element associated therewith, a rotatablecontrol unit having a seriesv of radiation transmitting areas adapted topass between said radiation emitting and radiation sensitive elements,and a shield for limiting transmission of radiations to a single controlunit transmission area; means including a rotatable feed unit forpassing between said elements in operative relation to said control unita ribbon having a longitudinal row 55 of alternating radiationtransmitting and radiation obstructing areas, a rotatablemember, anelectric motor responsive to said radiation sensitive element mountedthereon, one unit having a shaft coaxial with said member, driving con-70 nections between said motor and said shaft, and means for rotatingsaid member and the other unit in predetermined speed.

2. In a ribbon feeding apparatus comprising a radiation emittingelement, a radiation sensi- 75 tive element associated therewith, arotatable control unit having a series of radiation transmitting areasadapted to pass between said radiation emitting and radiation sensitiveelements, and a shield for' limiting transmission of radiations to angle control unit transmission area; means inc uding a rotatable feedunit for passing between said elements in operative relation to saidcontrol unit a ribbon having a longitudinal row ot alternating radiationtransmitting and radiation obstructing areas, a rotatable member, apinion rotatable with said member, means rotatably supporting one uniton said member, a pair of gears rotatably attached to said unit andmeshing with said pinion, a ring rotatably mounted on said member andhaving teeth in mesh with said gears, means responsive to said radiationsensitive element for rotating said ring and means for rotating saidmember and the other unit in predetermined speed relation.

3. In motion picture apparatus, the combination with a rotatable opticalcompensator of a radiation emitting element, a radiation sensitiveelement associated therewith, a rotatable control unit having a seriesof radiation transmitting areas adapted to pass between 'said radiationemitting and radiation sensitive elements, means including a rotatablefeed unit for passing between said elements in operative relation tosaid control unit and in operative relation to said optical compensatorlm having a. longitudinal row of alternating radiation transmitting andradiation obstructing areas adapted to register with said control unittransmission areas, a shield for limiting transmission of radiations toa single control unit transmission area, primary means for rotating saidcontrol unit and feed unit in predetermined speed relation to saidcompensator, and secondary means responsive to said radiation sensitiveelement connected between said primary means and one of said units forvarying the speed relation between one of said units and saidcompensator.

4. In motion picture apparatus the combina tion with a rotatable opticalcompensator of a radiation emitting element, a radiation sensitiveelement associated therewith, a rotatable control unit having a seriesof radiation transmitting areas adapted to pass between said radiationemitting and radiation sensitive elements, means including a rotatablefeed unit for passing between said element in operative relation to saidcontrol unit and in operative relation to said optical compensator imhaving a longitudinal row of alternating radiation transmitting andradiation obstructing areas adapted to register with said control unittransmission areas, a shield for limiting transmission of radiations toa single control unit transmission area, a rotatable member on which oneunit is rotatably mounted, means responsive to said radiation sensitiveelement for effecting rotation of said unit relative to said member, andmeans for rotating said member and the second unit in predeterminedspeed relation to said compensator.

5. In motion picture apparatus, the combina- .tion with a rotatableoptical compensator of a radiation emitting element, a radiationsensitive element associated therewith, a rotatable control unit havinga series of radiation transmiting areas adapted to pass between saidradiation emitting and radiation sensitive elements, means including arotatable feed unit for passing between said element in operativerelation to said control unit and in operative relation to said opticalcompensator film having a longitudinal row of aiternating radiationtransmitting and radiation obstructing areas adapted to register withsaid control unit transmission areas, a shield for limiting transmissionoi' radiations to a single con- -trol unit transmission area, arotatable member. an electric motor responsive to said radiationsensitive element mounted thereon, one unit having a shaft coaxial withsaid member, driving connections between said motor and said shaft. andmeans for rotating said member and the second unit, in predeterminedspeed relation to said compensator.

6. In motion picture apparatus. the combination with a rotatable opticalcompensator oi a radiation emitting element, a radiation sensitiveelement associated therewith, a rotatable control unit having a serieso! radiation transmitting areas adapted to pass between said radiationemitting and radiation sensitive elements, means including a rotatablefeed unit for passing between said element in operative relation to saidcontrol unit and in operative relation to said optical compensator illmhaving a longitudinal row oi' alternating radiation transmitting andradiation obstructing areas adapted to register with said control unittransmission areas, a shield for limiting transmission of radiations toa single control unit transmission area, a rotatable member, a pinionrotatable with said member. means rotatably supporting one unit on saidmember. a pair o! gears rotatably attached to said unit and meshing withsaid pinion, a ring rotatably mounted on said member and having teeth inmesh with said gears, means responsive to said radiation sensitiveelement for rotating said ring, and means for rotating said member andthe second unit in predetermined speed relation to said compensator.

7. In motion picture apparatus according to claim 3, a control lmitcomprising a cylinder surrounding one of said elements and having aseries of peripheral radiation transmitting areas.

